class StampedVersion:

    def __init__(self, vs, v):
        self.viewstamp = vs
        self.version = v

class ReplicationCommand:

    def __init__(self, seq, stamped_versions=[]):
        self.seq = seq # note: this seq field differs from that of a viewstamp
        self.versions = stamped_versions

class ReplicationReply:

    def __init__(self, seq = 0, ok = False, vid = 0):
        self.src = None
        self.seq = seq
        self.ok = ok
        self.vid = vid

